Aquatic Invasive Species

What are AIS?

Aquatic invasive species (AIS) (sometimes called exotic, nuisance, non-indigenous or non-native) are organisms that have escaped their native range and invaded foreign ecosystems. These species outcompete native species for resources, and without predators to keep population levels in check, they reproduce and spread. Their presence harms native ecosystems, which has a negative ripple effect on the commercial, agricultural, and recreational activities dependent on these ecosystems. They even have the potential to harm our health.

The establishment of aquatic invasive species in the Great Lakes has caused major ecological and economic impacts. These species have entered the Great Lakes a variety of way including ballast water from shipping vessels, canals, aquarium releases, bait release, and intentional stocking by management agencies. The Great Lakes currently contain over 180 identified non-native species.

Recently, the acronym “AIS” has replaced “ANS” (aquatic nuisance species) in many situations. However, national legislation enacted in the past used “ANS”, thus both “ANS” and “AIS” are used interchangeably and in general, can be considered synonymous.

How do I identify new invasive species?

Aquatic Invaders is a field guide to help with the identification of new invasive species. The species included have the highest risk for introduction to the Great Lakes. Also included are tips for distinguishing potential invaders from fish already present in the basin.